♻️ refactor some monitoring configs

modules/monitoring/default.nix

@@ -0,0 +1,17 @@
+_:
+
+{
+  services = {
+    prometheus = {
+      enable = true;
+      port = 9090;
+      exporters = {
+        node = {
+          enable = true;
+          enabledCollectors = [ "systemd" ];
+          port = 9100;
+        };
+      };
+    };
+  };
+}